A display device occupies an important portion in electronic devices, including a video device, a notebook, a monitor and a mobile communication device. In addition to a conventional LCD panel that maintains a sheet form, flexible display devices capable of bending and folding, such as a flexible panel and electronic paper, are shown.
In applying the flexible display device to a video device and a communication device, a plurality of patents was suggested, including a patent (Korean Patent Application No. 10-2008-0012667) of a form in which an image display surface is directed toward an outside surface and a central portion is directly folded in the state in which the image display surface and the outside surface turn against each other, a patent (Korean Patent. Application No. 10-2010-0062787) into which a hinge for absorbing a change in the length by changing the direction of the end of a flexible display device on one side to the inside using a roller within a edge located on the side opposite the hinge without directly fixing the end on one side and then applying a spring to the changed end of the flexible display device on one side has been incorporated, and a patent (Korean Patent Application No. 10-2012-0068710) to which a link member for absorbing a change in the length of a portion corresponding to the length of the circumference of a edge portion, which is folded upon unfolding and folding, by applying the link member that substitutes the function of a hinge has been applied.
However, the patent (Korean Patent Application No. 10-2008-0012667) of a form in which the central portion is directly folded in the state in which the image display surface is directed toward the outside surface and they have been turned against each other may maintain the state, such as an unfolded notebook, but may fall backward due to the instability of the distribution of weight. Furthermore, there is a possibility that a portion where bending is generated or a fixed end on any one side may be damaged due to the lack of the expandability of the flexible display device and related parts.
In the patent (Korean Patent Application No. 10-2010-0062787) into which the hinge has been incorporated and the patent (Korean Patent Application No. 10-2012-0068710) to which the link member has been applied, the flexible display device and related parts are not damaged in the place where bending is generated, but over-unfolding in the state, such as an unfolded notebook, is impossible.